The pet cat was dead and the cabin on Grand Lake was filled with smoke by the time its resident, Jim Weber, returned from work.

The culprit, authorities found, was one of seven space heaters Weber left running to warm the summer home. A cord melted and sparked a blaze that lit up the carpet and the wall, spreading through the rest of the house in the Stearns County town of Rockville on Jan 14.

Space heaters also have been linked to recent fires that left a father and his son unconscious in St. Paul and left six people homeless in Alden, near Albert Lea, after a resident tried to use a heater to warm frozen water pipes.

Such fires have had even deadlier results. A year ago, a space heater left running for days was tied to a fire that killed five young siblings in north Minneapolis and left their father and his two other children homeless.

Nationally, space heaters account for four out of five deaths caused by home heating malfunctions. Minnesota has seen 89 fires from space heaters over a recent five-year period, and authorities suspect there have been many more.

Accidents peak this time of year, as people across the Upper Midwest heat their homes at full blast.

REN&#xc9;E JONES SCHNEIDER &#x2022; reneejones@startribune.com

FATAL FIRE: The cause of a fire that killed five siblings last year in north Minneapolis was undetermined though the Fire Department said a space heater had been operating for days.

Officials say consumers are still overlooking basic precautions even as manufacturers make the equipment safer, with automatic shut-offs if units fall over and timers that curb overheating.

Casidy Anderson, a risk reduction officer with the Minneapolis Fire Department, said people rely too much on safety features instead of ensuring they keep the units 3 feet from couches, curtains, and other objects, never leave them unattended, and plug the heaters in directly rather than use an extension cord.

Safety features on space heaters “definitely can lull people into a false sense of security,” Anderson said.

A flood of complaints

People have reported space heaters suddenly catching fire, causing extensive smoke damage, and a “smell of burning electronics … which quickly increased in intensity to a near choking level” to the U.S. Consumer Product Safety Commission, which has fielded 378 complaints about space heaters in the last four years.

A resident of Otsego, Minn., wrote to the commission in April 2012 that he smelled burning plastic from a heater he bought at Target. He quickly unplugged the heater after seeing it spark and smoke, and noticed that a knob had melted. “I feel that the chance for tragedy is extremely high with this unpredictable unit,” the consumer complained.

In October, a Danville, Va., resident wrote that an electric space heater she received as a gift caught fire the first time she plugged it in. The nurse and volunteer firefighter unplugged it and carried it to the front porch until the flames died out, though a “cloud of noxious, choking smoke” had already formed inside.

“I am horrified that in the year 2014 we still have so many poorly made, outright unsafe products flooding the American market,” wrote the consumer. “This is by no means the first space heater I have seen catch fire, but it is the first one I have seen do so within minutes of its first use.”

“There are good space heaters now, but what we found is in a lot of these fires, the space heater is cheaper,” said fire investigator Steven Heinrich.

He said some of the lower-end space heaters, known as milk house heaters, are intended more for a barn than a home. He said he once investigated a fatal fire in Duluth at a “hoarder’s house,” where evidence suggested that stacks of newspapers and magazines fell on milk house heaters and ignited.

Last January, he examined a fire in Clinton, Minn., that sent three people to the hospital and resulted in a 7-year-old girl getting frostbite as firefighters battled the blaze. There, too, a space heater was to blame.

While traditional space heaters had more exposed hot areas, modern ceramic units keep the exterior at a low temperature, which lessens the chance that they could burn someone or catch on fire. Some let you set a temperature that, once reached, prompts the machine to shut off.

“There’s so much newer technology — it’s much newer materials, and with that comes the added expense,” said Robert Green, senior design engineer at Dyson’s Chicago office. “But the other side is, it’s the added safety … there’s the efficiency and the reliability.”

• Check the cord and outlet for overheating; if it feels hot, turn it off.

Last year, Dyson recalled two models of bladeless electrical heaters that sell for about $400 after reports of 82 incidents of them short-circuiting and overheating, or having burned or melted internal parts. It was one of at least a dozen space-heater recalls over the last five years. Recalls at other companies followed reports that the machines were unexpectedly overheating and causing units to melt and catch fire, and igniting furniture and other nearby objects.

Green said Dyson contacted every owner of the models and made repairs to a component in the circuit board.

Deadly results

Last spring, St. Paul firefighters responded to flames shooting from a third-story apartment and pulled Fred Stewart Sr. and his 3-year-old son from the bathroom where they had taken shelter. Doctors at Regions Hospital hurried to the scene to treat the unconscious victims.

While the official cause of the fire was undetermined, city fire marshal Steve Zaccard said it probably started after a space heater was placed too close to the couch. “Especially the materials they’re [couches] made of these days, they can get going in a hurry,” he said. “The polyester and foam can be flammable.”

He said he’d rather see people use space heaters, however, than ovens for warmth, which sometimes happens in low-income areas with poorly heated rental units.

After a Valentine’s Day fire last year killed five young siblings — their father and two other children escaped — in north Minneapolis, the city’s Fire Department found that a space heater had been running for days in the same part of the duplex where the blaze started. The father, Troy Lewis, said he’d bought the heater for about $50 at Wal-Mart because the house was inadequately heated, and he had also been running the oven for warmth.

Without more evidence, the department ruled the fire’s cause undetermined.